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COMMON  TREES 

BY 

J.  FRANCIS  MACBRIDE 
Assistant  Curator  of  the  Herbarium 


Botany 

Leaflet  11 

Second  Edition 


FIELD  MUSEUM  OF  NATURAL  HISTORY 

CHICAGO 
1936 


The  Botanical  Leaflets  of  Field  Museum  are  designed  to  give 
brief,  non-technical  accounts  of  various  features  of  plant  life,  especially 
with  reference  to  the  botanical  exhibits  in  Field  Museum,  and  of  the 
local  flora  of  the  Chicago  region. 

LIST  OF  BOTANICAL  LEAFLETS  ISSUED  TO  DATE 

No.     1.  Figs $  .10 

No.    2.  The  Coco  Palm 10 

No.    3.  Wheat 10 

No.    4.  Cacao        10 

No.    5.  A  Fossil  Flower 10 

No.    6.  The  Cannon-ball  Tree 10 

No.    7.  Spring  Wild  Flowers 25 

No.    8.  Spring  and  Early  Summer  Wild  Flowers      .     .         .25 

No.    9.  Summer  Wild  Flowers 25 

No.  10.  Autumn  Flowers  and  Fruits 25 

No.  11.  Common  Trees  (second  edition) 25 

No.  12.  Poison  Ivy 15 

No.  13.  Sugar  and  Sugar-making 25 

No.  14.  Indian  Corn 25 

No.  15.  Spices  and  Condiments 25 

No.  16.  Fifty  Common  Plant  Galls  of  the  Chicago  Area        .25 

No.  17.  Common  Weeds 25 

STEPHEN  C.  SIMMS,  Director 


Field  Museum  of  Natural  History 

DEPARTMENT  OF  BOTANY 
Chicago,  1936 

Leaflet  Number  11 


COMMON  TREES 


AMERICAN  ELM 

( Ulmus  americana) 

Even  before  George  Washington  took  command  of  the 
Revolutionary  troops  under  the  now  famous  "Washington 
Elm,"  of  Cambridge,  Massachusetts,  the  elm,  native  to 
our  river  woods,  was  being  planted  as  a  shade  tree.  The 
Washington  tree  has  recently  died  but  many  of  its  con- 
temporaries are  still  among  the  finest  planted  examples 
of  this  historic  American  tree.  The  best-known  elm  near 
Chicago  is  probably  the  old  Blackhawk  Treaty  Tree  at 
Evanston. 

The  elm's  manner  of  growth  is  usually  very  charac- 
teristic, the  main  branches  being  nearly  upright  with  their 
foliage-bearing  terminal  branchlets  curving  and  drooping. 


Field  Museum  of  Natural  History 


FLOWERS  OF  AMERICAN  ELM 


For  a  few  days  in  very  early  spring,  long  before  the 
leaves  come  out,  the  twigs  appear  "fuzzy"  due  to  the 
opening  of  the  small  clustered  blossoms.  These  tiny  incon- 
spicuous flowers  are  followed  by  small  wafer-like  fruits. 


Common  Trees 


LEAVES  OF  AMERICAN  ELM 

The  slippery  elm,  so-called  because  of  its  mucilaginous 
inner  bark,  may  be  distinguished  by  the  very  rough  upper 
surfaces  of  its  leaves.  The  leaves  of  the  cork  elm,  another 
rather  common  species,  are  smooth  on  both  sides  and  the 
branches  are  usually  corky  ridged.     (Elm  Family) 


Field  Museum  of  Natural  History 


COTTONWOOD  CATKINS 


Common  Trees 


COTTONWOODS 
(Populus  species) 

The  cottonwoods  or  poplars  belong  to  the  willow 
family,  but  our  species  are  all  easily  distinguished  from 
the  willows  by  their  broad,  somewhat  heart-shaped  leaves. 
The  leaf  stalks  of  most  species  are  flattened  at  right 
angles  to  the  leaf  blades,  which  accounts  for  the  charac- 
teristic trembling  of  the  foliage  in  the  slightest  breeze. 

The  sticky  buds  begin  to  swell  in  early  spring  and  the 
long  drooping  catkins  of  flowers  emerge  before  the  leaves. 
The  familiar  "cotton"  that  for  a  time  is  so  conspicuous 
about  the  tree  contains  the  ripe  seeds,  which  are  thus 
readily  dispersed  by  the  wind. 

The  white  or  silver  poplar,  the  Lombardy  poplar  with 
characteristic  spire-like  habit,  and  the  aspen  are  species 
of  cottonwoods.    (Willow  Family) 


Field  Museum  of  Natural  History 


WILLOWS 

(Salix  species) 

One  of  the  welcome  signs  of  spring  is  the  "pussy 
willow."  It  is  the  opening  catkin  of  the  male  flowers, 
with  numerous  tiny  willow  blossoms  partly  concealed 
and  protected  by  an  abundance  of  soft  hairs.  Female 
flowers  grow  on  separate  plants.  In  some  species  the 
catkins  appear  with,  in  others  before,  the  leaves. 


Common  Trees 


FRUITING  CATKINS  OF  WILLOW 

Only  a  few  of  the  very  many  species  are  trees.  An 
example  is  the  white  willow  said  to  have  been  brought 
over  from  Europe  by  the  Pilgrims.  The  black  willow 
is  perhaps  the  most  easily  recognized  of  all  species  because 
of  the  presence  of  two  ear-like  appendages  at  the  base 
of  each  leaf.     (Willow  Family) 


Field  Museum  of  Natural  History 


FLOWERING  WALNUT 


Common  Trees 


BLACK  WALNUT 

(Juglans  nigra) 

To  many  "black  walnut"  suggests  fine  old  furniture 
rather  than  the  tree  that  supplies  the  wood. 

The  leaves  of  this  valuable  tree  consist  of  many 
leaflets  along  a  central  stalk.  The  edible  fruit  is  well 
known,  and  so  is  the  stain  from  the  fresh  hull. 

Black  walnut  is  now  often  cultivated  for  its  timber. 
It  is  also  a  desirable  shade  tree  although  it  bears  its  foliage 
for  only  a  short  season.     (Walnut  Family) 


10 


Field  Museum  of  Natural  History 


BUTTERNUT  IN  FLOWER 


Common  Trees 


11 


BUTTERNUT 

(Juglans  cinerea) 

The  white  walnut,  as  this  tree  is  often  properly  called, 
is  distinguished  from  the  black  by  the  clammy  character 
of  its  leaves  and  fruits.  The  nuts  are  good  while  fresh 
but  soon  become  rancid.  Like  the  black  walnut,  it  is  a 
handsome  tree  of  rich  woods.  The  leaves  of  the  walnuts 
and  butternuts  are  easily  distinguished  from  those  of  the 
hickories  by  their  more  numerous  leaflets.  (Walnut 
Family) 


12  Field  Museum  of  Natural  History 


HICKORIES 

(Carya  species) 

The  popular  hickory  nuts  of  markets  are  mostly  from 
the  shag-bark  hickory  shown  here.  It  is  a  fine  tree  with 
loose  or  shaggy  bark,  and  leaves  mostly  consisting  of  five 
leaflets.  The  nuts  of  the  related  bitternut  and  pignut 
hickories  are  bitter.  The  bark  of  these  two  species,  how- 
ever, is  never  loose  and  the  husk  of  the  fruit  is  compara- 
tively thin. 

Hickory  leaves  suggest  those  of  the  ash  but  unlike 
the  leaves  of  the  latter  they  are  placed  alternately  on  the 
branches. 

The  very  hard,  tough  wood  is  especially  desirable  for 
use  in  making  tool  handles.    (Walnut  Family) 


Common  Trees 


13 


BIRCHES  and  ALDERS 

(Betula  and  Alnus) 

Birches  and  alders  are  rather  small  and  slender  trees 
with  catkins  produced  either  before  or  with  the  finely 
or  sharply  toothed  leaves.  The  fruiting  catkins  of  the 
alder  are  cone-like  and  persist  on  the  tree  for  a  long  time. 
The  white  or  paper  birch,  often  grown  for  ornament,  was 
the  canoe  birch  of  the  Indians.     (Birch  Family) 


14 


Field  Museum  of  Natural  History 


BEECH  FRUIT 


Common  Trees 


15 


BEECH 

(Fagus  grandifolia) 

The  smooth  light-gray  bark  of  the  tall-growing  beech 
can  be  recognized  from  afar.  The  tree,  moreover,  has  the 
habit  of  growing  in  groves  or  "pure  stands"  on  rich 
uplands. 

Its  leaves  are  strongly  parallel- veined.  The  nuts  are 
yellowish  and  when  ripe  in  late  autumn  have  a  sweet 
kernel.  Beech  wood  is  considered  particularly  desirable 
for  smoking  meats.  It  is  also  used  in  the  manufacture 
of  creosote  and  for  furniture  and  tools.     (Beech  Family) 


16 


Field  Museum  of  Natural  History 


WHITE  OAK 
(Quercus  alba) 
The  acorn  is  the  unique  and  well-known  fruit  of  the 
oak.     It  is  interesting  to  observe  the  different  kinds,  for 
they  differ  in  size  and  shape  for  each  species  of  oak. 


Common  Trees 


17 


WHITE  OAK  CATKINS 


There  are  even  several  closely  related  kinds  of 
white  oaks.  A  common  one  is  the  bur  oak  with  shaggy 
acorn  cups.  Another  is  the  swamp  white  oak.  Its  leaves, 
and  those  of  its  relatives,  the  chestnut  oaks,  are  very 
shallowly  lobed,  or  have  a  margin  merely  wavy.  (Beech 
Family) 


18 


Field  Museum  of  Natural  History 


RED  OAK 

(Quercus  species) 

This  group  of  oaks,  which  includes  the  black  oaks, 
is  easily  recognizable  from  all  the  white  oaks  by  the 
sharp  or  bristle-like  points  of  the  leaf  lobes.  The  various 
r.ed  oaks  are  closely  related  and  consequently  distinguished 
with  difficulty.  Their  wood  is  used  mostly  for  cheap 
furniture.  The  white  oaks  supply  more  valuable  wood 
for  general  construction  and  for  furniture.    (Beech  Family) 


CHESTNUT  BURS 


Common  Trees 


19 


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AMERICAN  CHESTNUT 
(Castanea  dentata) 

This,  the  true  American  chestnut,  is  related  to  the 
oaks  and  beeches.  Its  prickly  burs  open  on  the  tree  after 
heavy  frosts,  releasing  the  sweet  nuts  which  are  familiar 
to  us  as  "roasted  chestnuts."  The  tree  is  tall  and  stately, 
a  rapid  grower,  and  is  often  planted  for  ornament.  (Beech 
Family) 


20 


Field  Museum  of  Natural  History 


BLACK  CHERRY  FRUIT 


Common  Trees 


21 


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BLACK  CHERRY 

(Prunus  serotina) 
The  black  fruit  of  the  rum  cherry,  ripe  in  late  summer, 
is  better  known  than  the  attractive  white  blossoms  borne 
in  the  spring.  The  tree  grows  in  mixed  woods  and  usually 
is  rather  irregular  in  form,  although  large  and  tall.  The 
bitter  bark  is  the  source  of  a  tonic  drug.  This  cherry 
is  related  to  the  grape  or  bird  cherry  of  Europe.  (Rose 
Family) 


22 


Field  Museum  op  Natural  History 


PLANE  TREE.     SYCAMORE 
(Platanus  occidentalis) 

The  rather  maple-like  foliage  and  the  characteristic 
pendent  balls  or  "buttons"  of  small  flowers  or  fruits  and 
the  smooth  bark  peeling  off  in  broad  plates  are  the  con- 
spicuous features  of  this  tree.  Sometimes  it  is  called 
buttonwood. 

It  is  at  home  in  rich  soils  along  streams  where  it  is 
one  of  our  largest  and  finest  trees.     (Plane  Tree  Family) 


Common  Trees 


23 


LOCUSTS 
(Gleditsia  and  Robinia) 
The  picture  shows  the  pods  of  the  honey  locust,  a 
large  thorny  tree  with  small  green  flowers  that  is  often 
planted.  The  common  or  black  locust  has  clusters  of 
large  fragrant  white  flowers  and  fewer  and  larger  leaflets. 
It  is  not  thorny.     (Pea  Family) 


24 


Field  Museum  of  Natural  History 


TREE  OF  HEAVEN 

(Ailanthus  altissima) 
This  tree  can  be  distinguished  easily  from  any  other 
by  its  extremely  long,  compound  leaves  with  very  many 
leaflets,  mostly  borne  near  the  tips  of  the  thick  branches. 
The  branches  are  unusually  robust  and  stocky.  The 
small  male  and  female  flowers  are  produced  on  different 
individuals.  The  winged  fruits,  in  large  clusters,  ripen 
late  in  autumn. 


Common  Trees 


25 


FRUIT  OF  TREE  OF  HEAVEN 

The  common  name  is  said  to  refer  to  the  great  height 
the  tree  attains  in  China,  its  native  land.  It  is  frequent 
in  America  as  a  shade  tree,  particularly  in  cities,  because 
of  its  immunity  to  smoke.  Since  it  spreads  by  "suckers" 
it  often  forms  clumps  of  many  stems.    (Quassia  Family) 


26 


Field  Museum  of  Natural  History 


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FLOWERS  OF  RED  MAPLE 


Common  Trees 


27 


RED  MAPLE 

{Acer  rubrum) 

In  early  spring  the  bright  red  flowers  of  the  swamp 
or  red  maple  cover  the  leafless  twigs  and  redden  the  low- 
land maple  woods.  In  autumn  the  leaves  turn  crimson. 
They  are  characterized  by  the  oblong  or  parallel-edged 
base  of  the  middle  lobe. 

This  maple  is  sometimes  planted  as  a  shade  tree. 
(Maple  Family) 


28 


Field  Museum  of  Natural  History 


Common  Trees 


29 


SUGAR  MAPLE 
{Acer  saccharum) 

The  sugar  or  rock  maple  is  the  source  of  maple  sugar, 
and  its  wood  is  highly  valued.  It  is  a  slow-growing 
tree  found  in  rich  woods  and  is  planted  generally  for  its 
dense  shade  and  for  its  brilliant,  yellow  and  scarlet 
autumn  foliage. 

The  sugar  maple  unfolds  its  flowers  and  leaves  at  the 
same  time.  Its  leaves  are  lobed  but  not  toothed.  (Maple 
Family) 


30 


Field  Museum  of  Natural  History 


ASHES 
(Fraxinus  species) 

The  foliage  of  the  ash  tree  suggests  that  of  the  hickory, 
but  the  leaves  of  the  ash  are  placed  opposite  each  other. 
The  fruit  is  winged,  as  is  that  of  the  maple,  although  it 
is  not  double  like  the  latter,  and  it  is  often  borne  in  large 
masses.  The  blossoms  come  out  in  tight  bunches  before 
the  foliage. 


Common  Trees 


31 


FRUITS  OF  ASH 


The  ash  is  one  of  the  last  trees  to  leaf  out  in  the 
spring,  along  with  the  oak  and  walnut,  but  drops  its 
leaves  early  in  the  fall.  Among  the  ashes  are  several 
species  with  exceptionally  tough  wood.     (Olive  Family) 


32 


Field  Museum  of  Natural  History 


HORSE  CHESTNUT 


Common  Trees 


33 


HORSE  CHESTNUT.     BUCKEYE 
(Aesculus  species) 

The  horse  chestnut  need  never  be  confused  with  the 
chestnut,  if  the  decided  difference  in  the  leaves  is  noticed, 
for  they  consist  of  seven  leaflets,  spreading  fan-like  from 
the  end  of  the  leaf  stem. 

The  horse  chestnut  is  a  European  tree  commonly 
planted,  and  now  also  escaped  from  cultivation,  in  this 
country.  It  has  pyramidal  clusters  of  showy  white 
flowers  spotted  with  purple  and  yellow.  The  Ohio  buck- 
eye is  a  similar  native  tree  but  with  usually  only  five 
leaflets,  smoother  fruit,  and  much  less  conspicuous  blos- 
soms.    (Buckeye  Family) 


34 


Field  Museum  of  Natural  History 


LINDEN.     BASSWOOD 
(Tilia  americana) 

This  is  the  famous  "bee- tree"  of  rich  woods,  its 
fragrant  cream-colored  flowers,  which  appear  in  May 
or  June,  attracting  myriads  of  bees.  The  honey  is  highly 
prized,  especially  by  those  who  have  become  accustomed 
to  it. 


Common  Trees 


35 


LINDEN  FRUIT 

The  linden  is  a  beautiful  tree  with  a  rounded  top. 
It  has  an  abundance  of  large  heart-shaped  leaves  and  is 
a  favorite  shade  tree.  Its  flower  and  fruit  stalks  seem- 
ingly come  out  of  the  center  of  a  wing-like  structure. 
The  round   fruit  is  dry  and  woody.      (Linden  Family) 


36 


Field  Museum  of  Natural  History 


PODS  OF  CATALPA 


Common  Trees 


37 


Courtesy  of  Frank  M.  Woodruff,  Curator,  The  Chicago  Academy  of  Sciences 


CATALPA 

(Catalpa  species) 

The  catalpa  and  the  horse  chestnut  are  our  showiest 
trees  when  in  bloom.  The  catalpa  has  loose  clusters  of 
large  bell-shaped  white  flowers,  which  bloom  for  several 
weeks.  The  very  large,  heart-shaped  leaves  borne  on 
long  stalks  mark  the  tree  well.  Its  long  cylindrical  pods, 
known  as  Indian  beans,  filled  with  winged  seeds,  remain 
on  the  tree  until  spring. 

The  catalpa  has  been  generally  planted  for  ornament, 
and  in  groves  for  its  rapid  production  of  rot-resistant  wood, 
but  the  tree  is  readily  injured  by  the  wind  and  is  very 
subject  to  attack  by  insects.    (Trumpet  Vine  Family) 


38 


Field  Museum  of  Natural  History 


white  PINE 


Common  Trees 


39 


PINE 
(Pinus  species) 

There  are  many  different  species  of  pines,  but  they 
can  all  be  recognized  from  other  evergreen  trees  by  the 
bundled  needle-like  leaves.  The  white  pine  shown  in  the 
picture  has  five  needles  in  each  bundle ;  most  other  species 
have  only  two  or  three. 

Pines  grow  in  the  northern  hemisphere  and  are  very 
important  timber  trees.  Some  have  large  seeds,  known 
as  "pine  nuts."     (Pine  Family) 


40 


Field  Museum  of  Natural  History 


spruce 


Common  Trees 


41 


SPRUCE 
(Picea  species) 

Spruces  are,  perhaps,  the  most  popular  evergreens  in 
cultivation.  Their  branches  are  usually  arranged  closely 
in  whorls,  which  partly  accounts  for  their  dense  habit. 
Colorado  spruce,  often  planted,  has  a  gray-blue  hue. 

The  needles  of  the  spruce  always  occur  singly  on  the 
branchlets  and  are  never  in  bundles.  The  cones  do  not 
fall  readily  or  break  up.     (Pine  Family) 


42 


Field  Museum  of  Natural  History 


fir 


Common  Trees 


43 


FIR 

(Abies  species) 

The  fir  trees  are  very  similar  to  spruces  in  general 
appearance  and  also  have  their  needles  borne  singly. 
They  can  be  distinguished  easily  if  the  leaves  are  closely 
observed,  for  these  are  flat.  Those  of  the  spruce  are 
keeled  on  both  surfaces,  making  them  four-sided. 

Some  species  of  firs  are  among  our  largest  and  most 
valuable  timber  trees.     (Pine  Family) 


44 


Field  Museum  of  Natural  History 


TAMARACK.     LARCH 

(Larix  species) 
In  the  summertime  this  tree  with  spreading  branches 
resembles  an  evergreen  but  its  soft  leaves  or  needles  fall 
with  the  frost.  They  are  in  bundles  like  those  of  the 
pine,  but  there  are  many  of  them  in  each  bundle  and  they 
are  borne  on  a  curious  knob.  The  tamarack  grows  in 
swamps.     (Pine  Family) 


